Myocytes, CardiacHeartMyocardiumCell DifferentiationCells, CulturedEmbryonic Stem CellsGene Expression Regulation, DevelopmentalStem CellsSignal TransductionCell LineageTranscription FactorsCell LineEmbryo, MammalianEmbryo, NonmammalianRNA, MessengerGene Expression RegulationCell DivisionMice, Inbred C57BLMolecular Sequence DataMice, TransgenicCell ProliferationMice, KnockoutReverse Transcriptase Polymerase Chain ReactionTretinoinDNA-Binding ProteinsAnimals, NewbornBase SequenceGene ExpressionHomeodomain ProteinsPhenotypeImmunohistochemistryApoptosisTime FactorsCell Culture TechniquesChick EmbryoTranscription, GeneticEmbryonic DevelopmentCell CycleIn Situ HybridizationTransfectionModels, BiologicalCell SurvivalBlotting, WesternPluripotent Stem CellsGene Expression ProfilingMorphogenesisFlow CytometryNuclear ProteinsPromoter Regions, GeneticSex DifferentiationMesodermTrans-ActivatorsAmino Acid SequenceUp-RegulationRats, Sprague-DawleyMutationRepressor ProteinsEndodermCarcinoma, EmbryonalBlastocystDown-RegulationPhosphorylationCardiomegalyTumor Cells, CulturedMesenchymal Stromal CellsCell NucleusCell AggregationDNA PrimersFluorescent Antibody TechniqueTeratomaHematopoietic Stem CellsCalciumMyocardial ContractionZebrafishBasic Helix-Loop-Helix Transcription FactorsOctamer Transcription Factor-3Bone Marrow CellsFibroblastsNeuronsCoculture TechniquesAntigens, DifferentiationMembrane ProteinsB-LymphocytesCell MovementGreen Fluorescent ProteinsOsteogenesisRats, WistarXenopus ProteinsDimethyl SulfoxideMuscle DevelopmentCell CommunicationEpithelial CellsOsteoblastsRNA InterferenceMicroscopy, FluorescenceBone Morphogenetic ProteinsRegenerationEmbryonal Carcinoma Stem CellsEnzyme ActivationMyoblasts